The Impact of a Low or High Phosphate Diet on Phosphate and Calcium Excretion in Healthy People

Not Applicable

• Conditions: Aging; Nutrient; Excess; Cardiovascular Diseases
• Interventions: Dietary Supplement: Phosphate supplemented diet

• Registration Number: NCT04013776
• Lead Sponsor: Clinical Evaluation Research Unit at Kingston General Hospital

Brief Summary

Phosphate is present in many of the foods that the investigators eat and is required by many cellular processes. The kidneys are the only organ that excrete the extra phosphate from the diet that the body does not require. Phosphate is linked to vascular calcification and cardiovascular disease. Measures of serum phosphate do not reflect the burden of phosphate and are not sensitive to early changes in the way the kidneys eliminate phosphate. This study will determine whether the kidneys handle an oral phosphate load differently after 5 days of a low phosphate diet compared to 5 days of a high phosphate diet.

Detailed Description

In this study, participants will follow a low-phosphorus diet (750 mg) with a 500 mg calcium supplement for 5 days keeping a detailed diary of the foods eaten during this period. On the 5th day, the participant will undergo a 24 hour urine collection. Participants will present after an overnight fast for baseline blood and urine measurements. Then they will consume water containing 500 mg of phosphorus. Urine and blood will be collected every hour for 3 hours for measurement of phosphate and calcium and for measurement of hormones known to regulate phosphate and calcium including fibroblast growth factor-23, parathyroid hormone and vitamin D. One week later, participants will follow the same diet but will also receive a 1250 mg phosphorus supplement for 5 days. On the 5th day, urine will be collected for 24 hours. Participants will present again after an overnight fast and undergo the identical testing.

Study Timeline

• Study Start: 2017-05-01
• Status Verified: 2019-07
• Study First Submitted: 2019-07-08
• Study First Submitted QC: 2019-07-09
• Study First Posted: 2019-07-10
• Last Update Submitted: 2019-07-10
• Last Update Posted: 2019-07-12
• Primary Completion: 2019-09-30
• Study Completion: 2019-09-30

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• healthy
• between ages of 20 and 40

Exclusion Criteria

• known heart disease
• known diabetes
• pregnant
• breast-feeding

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Phosphate supplemented diet	Phosphate supplemented diet	All participants will undergo phosphate testing after following a phosphate supplemented diet for 5 days

Primary Outcome Measures

Name	Time	Method
Urinary phosphate excretion	3 hours	Change in urinary phosphate excretion after 500 mg phosphorus challenge

Trial Locations

Locations (1)

Queen's University; 🇨🇦 Kingston, Ontario, Canada